Probabilistic Sorting Memory Constrained Tree Search Algorithm for MIMO System

Considering the shortcomings of large storage space requirements and high complexity in multiple-symbol differential detection algorithm in current Multiple Input Multiple Output (MIMO) system, this paper proposes a probabilistic sorting memory constrained tree search algorithm (PSMCTS) by using performance advantage of sorting algorithm and storage advantage of memory constrained tree search (MCTS). Based on PSMCTS, a pruning PSMCTS named PPSMCTS is put forward. Simulation results show that the performance of PSMCTS is approach to that of ML algorithm under fixed memory situations, while the computational complexity is lower than that of MCTS algorithm in small storage capacity conditions under low signal noise ratio (SNR) region. PPSMCTS has more prominent advantages on reduction of computational complexity than PSMCTS algorithm. Theoretical analysis and simulation demonstrate that the two proposed algorithms can effectively inherit the good feature of MCTS algorithm, which are suitable for hardware implementation.